It's always difficult to give distant advice. First I would charge the battery thoroughly (better with a real wall charger than via the usb cable/pc). And start it again without the sd-card to see if it is the culprit.
And maybe it is really the refurbished device that is faulty. Try contact Pocketbook support again if nothing else helps.

thank you billi. I did all that. the only thing that I tempted to do is to download the latest software from web site and reflash again to see what happend. But I still waiting from PB support to reply my emails!!